Microchannel Particle Separation via Shear Lift Forces

Solution Overview

Problem

Conventional micro/nanoparticle filtration systems, including laboratory-on-a-chip applications, face limitations such as membrane clogging and pore size issues, making them less effective and costly for separating a wide range of particle sizes, and often require external force fields, increasing design complexity.

Innovation Solution

A microfluidic device with low aspect ratio microchannels that focuses particles into equilibrium positions using shear and wall lift forces, allowing for passive separation of particles by directing them into specific outlets based on size, without the need for external force fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If membrane-based filtering is used, then filtration efficiency is improved, but membrane clogging occurs and device complexity increases

Engineering Contradiction:

Improvefiltration efficiencyVSAvoidmembrane clogging

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the membrane component entirely from the filtration system, replacing it with a membrane-free microchannel structure that achieves particle separation through geometric confinement and flow dynamics rather than physical filtration barriers

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The microchannel structure uses its own geometric features (width, height, aspect ratio) and flow characteristics to automatically separate particles based on size, eliminating the need for external force fields or complex control systems

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If external force fields are used for particle separation, then separation capability is improved, but design complexity increases

Engineering Contradiction:

Improveseparation capabilityVSAvoiddesign complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The microchannel structure uses its own geometric features (width, height, aspect ratio) and flow characteristics to automatically separate particles based on size, eliminating the need for external force fields or complex control systems

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent varies the microchannel aspect ratio (width-to-height ratio) as a geometric parameter to control particle focusing and separation behavior, allowing different particle sizes to be separated by adjusting channel dimensions rather than adding complex external fields

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional filtration systems are used, then particle removal is achieved, but cost increases

Engineering Contradiction:

Improveparticle removalVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a simple microchannel structure that can be fabricated using low-cost techniques such as soft lithography or 3D printing, replacing expensive membrane materials and complex external field generation equipment

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent removes the membrane component entirely from the filtration system, replacing it with a membrane-free microchannel structure that achieves particle separation through geometric confinement and flow dynamics rather than physical filtration barriers

Inventive Principle:

Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables efficient, cost-effective, and high-throughput filtration of particles across a wide range of sizes and shapes, including nano- and micro-particles, without membrane clogging, using a passive method that simplifies design and reduces complexity.

Implementation Method 1

focusing a first portion of the particles into an equilibrium position in the microchannel

Methodology Applied

Scientific EffectShear lift force:

Implementation Method 2

focusing the particles directed therein into an equilibrium position in the microchannel

Methodology Applied

Scientific EffectWall lift force:

Data Source

PatentUS9987632B2Microfluidic methods for passive separation of cells and particles

Publication Date: 2018.06.05 UNIVERSITY OF CINCINNATI

AI summary

A method of separating a plurality of particles (14) from a portion of fluid, comprising directing the plurality of particles (14) into a microchannel (12). A first portion (16) of particles (14) is focused into an equilibrium position in the microchannel (12). The focused first portion (16) is directed into a first outlet (18) aligned with the equilibrium position. A portion of the fluid is directed into one or more outlets (20, 22). A microfluidic device (10) for separating a plurality of particles (14) from a portion of fluid, comprising a microchannel (12) having a first aspect ratio and a length L, thereby focusing the particles (14) directed therein into an equilibrium position in the microchannel, wherein at least a first portion (16) of the particles (14) focuses at distance X from a beginning of the microchannel (12). A first outlet (18) disposed after distance X and aligned with the equilibrium position to receive at least the first portion (16) of the particles (14) after the first portion (16) focuses into an equilibrium position in the microchannel (12). At least a second outlet (20) for receiving a second portion of the particles (14) before the second portion focuses into an equilibrium position.